A healthy couple is expecting their first child. The woman is 34 years old and is 16 weeks pregnant. Although she carries no major risk factors, she and her partner decide to opt for prenatal testing. The results of the tests show that their baby girl has Turner syndrome. This is a genetic disorder with a missing X chromosome leading to abnormalities such as short stature, dysfunctional gonads, and problems with the kidney, thyroid, and heart. However, a number of these problems can be treated. The question for the couple now is whether they decide to terminate the pregnancy or carry the child to full term.
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Prenatal diagnosis refers to tests performed on the unborn fetus with the aim of detecting genetic and chromosomal abnormalities, as well as birth defects. The most common noninvasive procedure is an ultrasound. This procedure can provide a lot of information about gestational age, fetal position, and can detect abnormalities with up to 90% accuracy.
PRENATAL DNA CAN BE OBTAINED
DIRECTLY FROM THE WOMAN'S BLOOD
Invasive techniques include amniocentesis, chorionic villus sampling, and fetal blood sampling from the umbilical cord. Amniocentesis can usually be performed only after the 14th week of pregnancy and takes at least a few weeks for the results to be obtained. On the other hand, chorionic villus can be done very early on in gestation (9-12 weeks) and takes only 24 hours for the results [1]. However, with such early testing comes a higher risk to the fetus.
Recently, genetic tests have also been developed, making it possible to analyze fetal DNA directly from the pregnant woman’s blood. But the commercialization of this latter group of tests has spurred a huge legal battle.
Genetic Testing: Criticisms and Defenses
The major ethical issue about prenatal testing is that it increases the number of abortions, potentially supporting the tenets of eugenics. Eugenics stems from the Greek words eu, meaning ‘good’, and -genēs, meaning ‘born’. It refers to the practice of improving the genetic quality of the human population [2]. This philosophy advocates the promotion of higher reproduction of people with positive traits (positive eugenics) and the reduced reproduction of people with less-desirable traits (negative eugenics).
The results of a prenatal test provides a couple with a lot of information about their unborn child. Naturally, one can see how this might lead to supporting eugenics. It is certainly wrong to abort a child based on sex, and some countries have even taken legal action to prevent this practice [3]. However, getting valuable information about the health of their child can make a couple more financially and emotionally prepared to receive their child. Some birth defects like spina bifida can be treated immediately after the child is born. Knowing about such conditions in advance can also prepare medical professionals for the birth.
Another problem that can arise with the birth of a child with a disorder can be the quality of relationship between the parents and the child. For example, parents may not be willing to let their child indulge in certain activities leading to a restriction in the child’s freedom. In addition, for late-onset genetic disorders, the issue of societal discrimination from employers and insurance companies is to be taken into account.
OLDER PREGNANT WOMEN ARE
ADVISED TO GET TESTED
What is often forgotten is that being a carrier for disease-linked genes does not guarantee getting the disease. Often, physical and environmental factors can influence genetic expression to a large extent. But do the benefits of prenatal testing outweigh the consequences of bringing a helpless baby who you know might suffer into this world?
When Should We Test?
Prenatal testing is usually advised for older pregnant women, couples who have a family history of genetic disorders or already have a child with a genetic disorder, and couples concerned about a specific disorder that might occur more frequently in their ethnic group [4]. On the other hand, every couple has the right to opt for prenatal testing as it provides valuable information about their child. While a negative result will certainly ease anxiety, a positive result will drastically change the couples’ lives. In addition, like all scientific tests, they are also not free from false positives and false negatives. In general, it is always recommended to speak to a genetic counselor before opting for a prenatal test.
The question about whether to test remains a personal matter of conscience, and ultimately, any decision that this couple takes will change their lives forever.
[1] Alfirevic Z et al, The Cochrane Coll, 2009
[2] National Library of Medicine, 2010
[3] Reproductive Health Matters, 2005, http://www.jstor.org/stable/3776292
[4] http://ubeclu.unibe.ch/insel/GENETEST.HTML
by Apoorva Rajiv Madipakkam, PhD Alumni AG Sterzer
This article originally appeared in CNS Volume 7, Issue 3, Nature vs Nurture
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